Check whether the function f given by f(x)=x100+sin x−1 strictly decreasing for the given interval.
(0,π2)
In interval (0,π2),cos x>0 and 100x99>0
∴100x99+cos x>0⇒f′(x)>0 in (0,π2)
Thus, f is strictly increasing in interval (0,π2)
Hence, function f is not strictly decreasing in the given intervals.